The last step to creating terrain is adding foliage.
The Content Browser has a Nature folder in the main Gallery folder that contains hundreds of flowers, trees, shrubs, and bushes. Some plants are themed according to seasons as well.
Decide on a season, then populate your terrain with different types of trees and plants. Place the plants sporadically, then scale and rotate them to add more variety to the landscape. You can also add fallen trees and broken stumps to give your terrain character.
Walking through a forest or looking in nature books will give you ideas for the types of trees that grow in certain climates and how trees grow and look in groups. Apply this to your terrain for a visually pleasing look.
Use tall grasses and swamp plants next to the water. Tall grass also looks good scattered next to the side of the road.

When placing foliage, group your trees, rocks, and flowers together in small clusters, and allow green spaces between the groups for a more natural look. This also lets players openly explore your island.

Use the search bar in the Content Browser to quickly find the kind of foliage you’re looking for.